Pervaporation processes with hydrophilic ceramic pervaporation membranes take place in order to carry out laboratory experiments. These types of experiments are executed to screen potential applications and to run small scale experiments to study ‘Proof of Principal’ and cleaning procedures.
Application Tester LTU-054 from Pervatech is designed for Ex zone 2 environments and water removal from flammable feed and for process conditions of 10 bar and 150°C (maximum), according to PED 97/23.
The unit features a frame, SS 316 tubing, appendages, membrane module, 5 litre feed vessel, double wall for heating with external oil-heating bath, a frequency controlled magnet driven turbine pump, a vacuum pump, the permeate collection and an electric control cabinet.
It works by the feed stream being re-circulated over the module, and transporting the water through the membrane with vacuum applied on the permeate side. The feed (liquid) comes from the feed tank with a capacity of 5 litre and is regulated by a frequency controlled turbine pump, which also facilitates the re-circulation over the module. The feed tank is heated by an external oil-heating bath. Temperature is controlled by a thermocouple type T and the safety limit set by a second thermocouple type T. The cross-flow over the membrane can be set by the frequency controller of the feed pump. The typical liquid linear velocity through the membrane module is about 1.5-2 m/s, to prevent concentration polarisation. Lower velocities will reduce the refreshing of the species to be transported through the membrane.
The permeate vapour is liquefied by the first condenser, which is cooled with cooling water while the remaining non-condensables are solidified in the cold traps, facilitated by liquid nitrogen, dry ice/acetone or any coolant serving the condensation as required. The fractionated condensation facilitates separating the higher boiling point species first, followed by solidification in the cold trap system. The vacuum is facilitated by means of a dry membrane vacuum pump.
The unit and membranes are suitable for dehydration of any kind of solvent and suitable for testing with different types of modules. Organophilic pervaporation is also possible with the appropriate membrane module.